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# setValue(_:forKey:)

Sets the specified property of the managed object to the specified value.

```
func setValue(_ value: Any?, forKey key: String)
```

## Parameters

`value`

The new value for the property specified by `key`.

`key`

The name of one of the receiver’s properties.

## Discussion

If `key` is not a property defined by the model, the method raises an exception. If `key` identifies a to-one relationship, relates the object specified by `value` to the receiver, unrelating the previously related object if there was one. Given a collection object and a key that identifies a to-many relationship, relates the objects contained in the collection to the receiver, unrelating previously related objects if there were any.

This method is overridden by `NSManagedObject` to access the managed object’s generic dictionary storage unless the receiver’s class explicitly provides key-value coding compliant accessor methods for `key`.

> Important:
> You must not override this method.

## See Also

[`setObservationInfo(_:)`](/documentation/CoreData/NSManagedObject/setObservationInfo(_:))

Sets the observation info of the managed object.


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